Description of Substance: Colorless to light-colored, viscous liquid with a mild, hydrocarbon odor.

LEL: . . Noncombustible Liquid

Original (SCP) IDLH for chlorodiphenyl (42% Cl): 10 mg/m3

Basis for original (SCP) IDLH: In the absence of any other toxicological data, the chosen IDLH is based on the human TCLO (resulting in an irritant effect) of 10 mg/m3 [Elkins 1959 cited by NIOSH 1976].

Original (SCP) IDLH for chlorodiphenyl (54% Cl): 5 mg/m3

Basis for original (SCP) IDLH: In the absence of human exposure data or data on acute animal exposure, data on chronic animal exposures were used to determine the IDLH. The chosen IDLH is based on inhalation exposure data reported by AIHA [1965] that indicated liver damage occurs in rats chronically exposed (7 hours/day for 83 exposures during 121 days) to 5.4 mg/m3 chlorodiphenyl (54% chlorine) [Treon et al. 1956].

Human data: It has been reported that concentrations above 10 mg/m3 were unbearably irritating [Elkins 1959]. Several deaths due to atrophy of the liver have occurred among workers chronically exposed to the fumes of chlorodiphenyls and chloronaphthalenes [von Wedel et al. 1943].

Revised IDLH: 5 mg/m3Basis for revised IDLH: The revised IDLH for chlorodiphenyl is 5 mg/m3 based on acute inhalation toxicity data in humans [Elkins 1959] and animals [Treon et al. 1956]. [Note: NIOSH recommends as part of its carcinogen policy that the “most protective” respirators be worn for chlorodiphenyl at concentrations above 0.001 mg/m3.]